I got further explanation from SteinAir regarding my circuit diagrams.

The unconnected circuit breakers simply represent the VPX, so those are not additional devices I need to buy or install.

Some of the other symbols are explained in this diagram they sent me.

So, since the external alternator and the starter contactor are on the engine side of the firewall, then I assume the 50A resettable circuit breaker is also on the engine side?  Seems like a strange place for a resettable circuit breaker...  Unless I drag wires through the firewall for that to be on the cabin side?

And the 25A and 5A fuses are also on the engine side?